1. Field of the Invention
The present invention relates to water treatment and more particularly to a domestic water supply settling tank sludge removal apparatus.
2. Description of the Prior Art
Sludge moving apparatus of the reciprocating bridge or carriage type is in common use in water purification plants in which a scraper blade is actuated for moving sludge and released to an idling position in response to back and forth movement of the bridge or carriage.
U.S. Pat. Nos. 2,660,557 and 3,868,323 are illustrative of sludge collecting apparatus. In a water purification plant the rate of settlement of sludge to be removed, such as sand, usually settles out at a known rate and it is therefore desirable that the sludge removing apparatus be automatic and operable at predetermined times both day and night. Further, the type of drive used for reciprocating the bridge or carriage has generally been a source of trouble particularly where cables are entrained over pulleys and used for effecting the reciprocating action of the scraper or where an elongated electric current supply cable is supported by a reel and used for operating an electric motor mounted on and reciprocated with the bridge.
This invention proposes mounting the bridge or scraper support carriage on wheels guided by tracks extending along tank wall copings and wherein a reversible electric motor is connected through a transmission with a friction drive wheel, contacting the tank wall, in response to gravitational attraction for the motor and wheel mass for reciprocating the bridge at predetermined times.